Spotlight on the Cytoskeleton

Technique allows researchers to see the inner workings of cellular scaffolding molecules actin and tubulin.

By Rina Shaikh-Lesko | May 27, 2014

EPFL, KAI JOHNSSONResearchers have developed a new way of visualizing cellular skeletons inside of living cells, according to a paper published last week (May 25) in Nature Methods. A team led by Kai Johnsson of the École Polytechnique Fédérale de Lausanne in Switzerland used fluorogenic probes that fluoresce when bound to actin or tubulin.

Because the probes are not toxic, they can be added to live cells in culture. The new technique builds upon a previous finding of a class of fluorescent molecules called silicon-rhodamine (SiR) derivatives. SiR derivatives emit light in the far-red range, which makes them easier to distinguish from background light sources. The researchers used stimulated emission depletion microscopy to obtain super-resolution images. They bound SiR molecules to docetaxel, an anticancer drug that binds tubulin, and to jasplakinolide, which binds to actin. Both molecules are able to cross the cell membrane and provide a view of the movement of the tubulin and actin cytoskeleton.

"You just add them directly into your cell culture, and they are taken up by the cells," Johnsson told BBC News.